Fertility changes in soils cultivated for wheat in southern New South Wales.

1961 ◽  
Vol 12 (4) ◽  
pp. 612 ◽  
Author(s):  
CH Williams ◽  
J Lipsett

A study has been made of red-brown earth�s cultivated for wheat on a narrow rotation of fallow-wheat-volunteer pasture in the Ariah Park district of Xew South Wales. Surface soil samples from 55 cropped paddocks currently under fallow and from matched adjoining areas with no history of cultivation were examined in laboratory, pot culture, and field studies. Many of the soils had carried at least 20 crops since being brought under cultivation and had lost an average of 30% of their organic matter during this period. However, only 17% of the organic phosphorus had been mineralized. The mean ratio of carbon : nitrogen : sulphur : organic phosphorus in the uncultivated soils was 178.3 : 10 : 1.37 : 0.63 while that for the cultivated soils was 170.9 : 10 : 1.41 : 0.74. As a result of the decrease in organic matter content the cation exchange capacity decreased under cultivation. Losses of the exchangeable cations also occurred, but the relative proportions of the metal ions in the cultivated soils were the same as those in the uncultivated. Removal of cations in crops could not account for all of the losses observed. There had been a net loss of sulphur from the surface soils over and above that likely by crop removal. The nitrate content of the surface samples was insufficient to provide the nitrogen uptake by the crop either in pots or in the field. Evidence is presented suggesting that other sources, including leached nitrate, were utilized in the field. Mineralization of organic phosphorus and fertilizer addition had increased the amounts of inorganic, plant-available forms, but the total phosphorus was unchanged in the cultivated soils. However, the phosphorus status of' the cultivated soils was still extremely low and responses to phosphorus were obtained at all sites. There seems little prospect of reducing current superphosphate rates on these soils.

2016 ◽  
Vol 2 (2) ◽  
pp. 37
Author(s):  
B.H. Prasetyo ◽  
N. Suharta ◽  
Subagyo H. ◽  
Hikmatullah Hikmatullah

Ultisols are a major group of marginal soils extensively found in the upland area of Indonesia. To better understand the potential of the Ultisols developed from claystone and sandstone in the Sasamba Integrated Economical Development Area in East Kalimantan, chemical and mineralogical characteristics of 27 Ultisols pedons consisting of 76 topsoil and 118 subsoil samples were investigated. Besides analysis and interpretation of data, relationships of several soil characteristics were constructed using simple regression. The results indicated that Ultisols showed acid to very acid reaction, had low content of organic matter and low base saturation. Soils generally exhibited net negative charge, and the point of zero charge was reached at pH 3.6. Both potential and available phosphates were low, and there was a trend that amorphous aluminum was responsible for phosphate fixation. The low content of exchangeable potassium in topsoil and subsoil indicated a positive correlation with potential potassium. Clay mineral was composed chiefly of kaolinite, with small amounts of illite, vermiculite, and quartz. The domination of kaolinite and low organic matter content causes the soils to have low cation exchange capacity. Soil management in this area should be focused on building up and maintaining soil fertility, and applying appropriate soil conservation techniques to minimize erosion. To obtain sustained productivity, various soil amendments including the use of farm and/or green manure, liming with agricultural lime, and application of rock phosphate and K fertilizers were highly recommended.


2008 ◽  
Vol 53 (No. 5) ◽  
pp. 225-238 ◽  
Author(s):  
N. Finžgar ◽  
P. Tlustoš ◽  
D. Leštan

Sequential extractions, metal uptake by <i>Taraxacum officinale</i>, Ruby&rsquo;s physiologically based extraction test (PBET) and toxicity characteristic leaching procedure (TCLP), were used to assess the risk of Pb and Zn in contaminated soils, and to determine relationships among soil characteristics, heavy metals soil fractionation, bioavailability and leachability. Regression analysis using linear and 2nd order polynomial models indicated relationships between Pb and Zn contamination and soil properties, although of small significance (<i>P</i> < 0.05). Statistically highly significant correlations (<i>P</i> < 0.001) were obtained using multiple regression analysis. A correlation between soil cation exchange capacity (CEC) and soil organic matter and clay content was expected. The proportion of Pb in the PBET intestinal phase correlated with total soil Pb and Pb bound to soil oxides and the organic matter fraction. The leachable Pb, extracted with TCLP, correlated with the Pb bound to carbonates and soil organic matter content (<i>R</i><sup>2</sup> = 69%). No highly significant correlations (<i>P</i> < 0.001) for Zn with soil properties or Zn fractionation were obtained using multiple regression.


2019 ◽  
Vol 34 (3) ◽  
pp. 362-370
Author(s):  
Jose V. Fernandez ◽  
D. Calvin Odero ◽  
Gregory E. MacDonald ◽  
Jason A. Ferrell ◽  
Brent A. Sellers ◽  
...  

AbstractDissipation of S-metolachlor, a soil-applied herbicide, on organic and mineral soils used for sugarcane production in Florida was evaluated using field studies in 2013 to 2016. S-metolachlor was applied PRE at 2,270 g ha−1 on organic and mineral soils with 75% and 1.6% organic matter, respectively. The rate of dissipation of S-metolachlor was rapid on mineral soils compared with organic soils. Dissipation of S-metolachlor on organic soils followed a negative linear trend resulting in half-lives (DT50) ranging from 50 to 126 d. S-metolachlor loss on organic soils was more rapid under high soil-moisture conditions than in corresponding low soil-moisture conditions. On mineral soils, dissipation of S-metolachlor followed an exponential decline. The DT50 of S-metolachlor on mineral soils ranged from 12 to 24 d. The short persistence of S-metolachlor on mineral soils was likely attributed to low organic matter content with limited adsorptive capability. The results indicate that organic matter content and soil moisture are important for persistence of S-metolachlor on organic and mineral soils used for sugarcane production in Florida.


Soil Research ◽  
2016 ◽  
Vol 54 (1) ◽  
pp. 11 ◽  
Author(s):  
Melinda R. S. Moata ◽  
Ashlea L. Doolette ◽  
Ronald J. Smernik ◽  
Ann M. McNeill ◽  
Lynne M. Macdonald

Organic phosphorus (P) plays an important role in the soil P cycle. It is present in various chemical forms, the relative amounts of which vary among soils, due to factors including climate, land use, and soil type. Few studies have investigated co-variation between P types or stoichiometric correlation with the key elemental components of organic matter– carbon (C) and nitrogen (N), both of which may influence P pool structure and dynamics in agricultural soils. In this study we determined the organic P speciation of twenty Australian Red Chromosols soils, a soil type widely used for cropping in Australia. Eight different chemical forms of P were quantified by 31P NMR spectroscopy, with a large majority (>90%) in all soils identified as orthophosphate and humic P. The strongest correlations (r2 = 0.77–0.85, P < 0.001) between P types were found among minor components: (i) between two inositol hexakisphosphate isomers (myo and scyllo) and (ii) between phospholipids and RNA (both detected as their alkaline hydrolysis products). Total soil C and N were correlated with phospholipid and RNA P, but not the most abundant P forms of orthophosphate and humic P. This suggests an influence of organic matter content on the organic P pool consisting of phospholipid and RNA, but not on inositol P or the largest organic P pool in these soils – humic P.


1970 ◽  
Vol 20 (2) ◽  
pp. 173-182
Author(s):  
KF Akhter ◽  
ZH Khan ◽  
MS Hussain ◽  
AR Mazumder

The seasonally flooded soils of Bangladesh are unique in respect of several specific characteristics and contribute toward producing bulk of its staple food - mainly rice. Having fine texture these soils are similar to the “paddy soils” of Southeast Asian floodplains and have high production potential under proper management. Six representative soil series, viz. Arial, Debidwar, Naraibag, Jalkundi, Siddirganj and Tippera from the central region of Bangladesh have been studied to evaluate some of their intrinsic physico-chemical properties and their sustainable management requirements. These soils are slightly acidic to neutral and are negatively charged with ΔpH values ranging between –0.2 and –1.2. The organic matter content in the surface soil is relatively low that decreases steadily with depth. The cation exchange capacity (CEC) of the soils varies on the basis of their clay and organic matter contents while base saturation per cent (BSP) is high. The contents of available N, P, K and S and DTPA-extractable Fe, Mn, Cu and Zn in soils are moderate and are commensurate with the contents of colloidal fractions. These soils receive several mineral nutrients annually with the sediments deposited during the monsoon floods. The characteristics like organic matter content, particle size distribution, CEC, pH and BSP that have important management implications have been discussed. Key words: Seasonally flooded soils; Physical and chemical attributes; Management implications DOI: http://dx.doi.org/10.3329/dujbs.v20i2.8978 DUJBS 2011; 20(2): 173-182


Author(s):  
Alma Pociene ◽  
Skirmantas Pocius

In Lithuania almost the whole drinking water is derived from groundwater sources. The concept of ground@water vulnerability is based on an assumption that a physical environment may provide some degree of protection to groundwater against human impact.The earth materials may act as natural filters to screen out some contaminants. Groundwater vulnerability depends on the natural characteristics of a site and relates to the pathways and rate of downward movement of pollutants. Pollutant migration through the soil zone depends just on the depth of waterlogging, texture, organic matter content, quantity of precipitation.. Pollutants accumulating in shallow groundwater in the Lithuanian area are, first of all, nitrates and organic matter. Regularities of groundwater chemistry can be determined only after investigation into the processes of their formation. That is why we need to find out the main factors of nitrate concentrations in groundwater. Investigation took place in Karkiškes object of Educational Farm of Lithuanian University of Agriculture in 1997–2002. Also, the data from publications were used. The regime of groundwater level and the quantity of nitrates in it was an object of the investigation. The objective of the thesis is to estimate correlation between nitrate concentrations in groundwater and natural factors, such as textural composition of the soil, the quantity of clay and humus particles in the soil, the depth up to the groundwater level, the depth of a restrictive layer and annual precipitation amount. The correlation analysis was used to determine relationship among these factors. The investigation shows that the concentration of nitrogen in groundwater and nitrate leaching are under the influence of humus and clay particles in the soil. It also shows that, when the content of clay particles in the soil increases, nitrogen leaching decreases. Relationship between nitrate content in groundwater and its level from the soil surface, precipitation amount were identified by the investigation. The obtained relationship is close enough, and the correlation coefficients are high (0,86–0,98).


Weed Science ◽  
1994 ◽  
Vol 42 (4) ◽  
pp. 629-634 ◽  
Author(s):  
Blake A. Brown ◽  
Robert M. Hayes ◽  
Donald D. Tyler ◽  
Thomas C. Mueller

Fluometuron adsorption and degradation were determined in soil collected at three depths from no-till + no cover, conventional-till + no cover, no-till + vetch cover, and conventional-till + vetch cover in continuous cotton. These combinations of tillage + cover crop + soil depth imparted a range of organic matter and pH to the soil. Soil organic matter and pH ranged from 0.9 to 2.5% and from 4.7 to 6.5, respectively. Fluometuron adsorption was affected by soil depth, tillage, and cover crop. In surface soils (0 to 4 cm), fluometuron adsorption was greater in no-till + vetch plots than in conventional-tilled + no cover plots. Soil adsorption of fluometuron was positively correlated with organic matter content and cation exchange capacity. Fluometuron degradation was not affected by adsorption, and degradation empirically fit a first-order model. Soil organic matter content had no apparent effect on fluometuron degradation rate. Fluometuron degradation was more rapid at soil pH > 6 than at pH ≤ 5, indicating a potential shift in microbial activity or population due to lower soil pH. Fluometuron half-life ranged from 49 to 90 d. These data indicate that tillage and cover crop may affect soil dissipation of fluometuron by altering soil physical and chemical properties that affect fluometuron degrading microorganisms or bioavailability.


1969 ◽  
Vol 39 (2) ◽  
pp. 65-76
Author(s):  
Fernando Abruña-Rodríguez ◽  
José Vicente-Chandler

The exchange capacity of the organic matter in typical soils of Puerto Rico was evaluated from: (1) The variation in the exchange capacity of soil samples following destruction of the organic matter, (2) titration curves of extracted organic matter, (3) and the correlations between exchange capacity and organic-matter content of soil samples. The first method was the most practical and gave fairly accurate results. The second method gave results which were in all cases too high. The third method, though probably the most accurate, is impractical. Results obtained with the first and third methods were similar. The exchange capacity of the organic matter varied rather widely, but was generally between 100 and 150 m.e. per 100 gm. On the average it accounted for about 25 percent of the total exchange capacity of the soils studied. The organic matter removed by flotation had the highest exchange capacity and the more readily oxidizable portions generally appeared to be the most active. This suggests the importance of conserving the more readily lost portions of the soil organic matter. A considerable portion of the soil organic matter was extremely resistant to oxidation, had a narrow C:N ratio, and apparently little exchange capacity. This suggests a close association between the organic matter and the inorganic soil colloids. The marked resistance to oxidation of a considerable portion of the organic matter may partly explain the high contents found even in continuously cultivated soils in Puerto Rico.


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